This invention is in the field of energetic munitions compounds, and particularly cyclic nitramines.
The propellant industry is constantly striving for compounds that have high energy and high density characteristics for use in munitions, including both explosives and propellants. Some current high volume ingredients such as cyclotrimethylenetrinitramine (RDX) and cyclotetramethylenetetranitramine (HMX) are very effective in providing energy for numerous munitions applications. The industry, however, continues to seek new compounds having densities near 2.0 g/mL, detonation pressures greater than 400 kbar, detonation velocities greater than 9000 m/sec, favorable oxygen balance, and good thermal and hydrolytic stability.
One candidate for this type of energetic compound is 2,4,6-trinitro-2,4,6-triaza-cyclohexanone (TNTC). This compound has a calculated density of near 2.0 g/mL, a favorable oxygen balance, a calculated detonation velocity of 9270 m/sec, and a calculated detonation pressure of 402 kbar. A comparison of the thermochemical properties of TNTC with those of RDX and HMX is shown in the table below.
TABLE I ______________________________________ Thermochemical Properties of RDX, HMX and TNTC (All values listed below are calculated values, except those marked with an asterisk, which are observed.) RDX HMX TNTC ______________________________________ Empirical Formula C.sub.3 H.sub.6 N.sub.6 O.sub.6 C.sub.4 H.sub.8 N.sub.8 O.sub.8 C.sub.3 H.sub.4 N.sub.6 O.sub.7 Oxygen Balance, % -21.6 -21.6 -6.8 Heat of Formation, +14.7* +17.9* -14.8 kcal/mole Heat of Explosion, -120 -120 -134 kcal/100 g Detonation Velocity, 8850 9160 9270 m/sec Detonation Pressure, 350 382 402 kbar Density, g/mL 1.82* 1.90* 1.97 ______________________________________
These figures show that TNTC is more energetic and more dense than both RDX and HMX. TNTC has a lower heat of formation but a more favorable oxygen balance than either of the other two. In addition, differential scanning calorimetry measurements show that TNTC has a sharp exotherm peak at 206.degree. C.
Known methods for forming TNTC involve reacting urea with formaldehyde and t-butylamine to give 4-t-butyltetrahydro-1,3,5-triazin-2-one, followed by nitration and nitrolysis to achieve the desired product. This procedure suffers from a low overall reaction yield and a product having less than optimal thermal stability, the latter possibly attributable to the presence of a high proportion of impurities.